1. Field of the Invention
The present disclosure relates generally to a power measurement system for multiple power sources and a method of operating the same, and more particularly to a power measurement system for multiple power sources and a method of operating the same that a multiplexer is included to be used.
2. Description of Prior Art
Reference is made to FIG. 1 which is a schematic circuit block diagram of a prior art power detection apparatus and a management apparatus thereof. The power detection apparatus and the management apparatus thereof are disclosed in TW Patent M385003. The power detection apparatus 10 includes an input current detector 111, an input voltage detector 112, and a digital microprocessor 12. The power detection apparatus 10 is applied to detect power of a computer system, in which the power system is a load 2 shown in the FIG. 1. A power source 1 provides an AC power and the AC power is converted into a DC power by a power converter 21, and then the DC power is converted into the required DC voltage by a power supply module 20 for supplying power to a load 2, such as a computer system. The power detection apparatus 10 is provided to accurately detect consumed power of the load 2 and a power supply in a single power-supplying loop, and further accurately detect consumed power in multiple power-supplying loops. In addition, the results of detecting consumed power are sent to a power management system via communication buses.
An input current IPI and an input voltage IPV are detected to calculate consumed power IPW of the computer system. In particular, the consumed power IPW is equal to IPI×IPV, namely, IPW=IPI×IPV.
The power detection apparatus 10 is mainly composed of an input detection module 11 and the digital microprocessor 12. The input detection module 11 is composed of the input current detector 111 and the input voltage detector 112. The input current detector 111 is connected in series to the power source 1 and the power converter 21 to detect the input current IPI between the power source 1 and the power converter 21, and then output the value of the input current IPI to the digital microprocessor 12. The input voltage detector 112 is connected in parallel to the power converter 21 to detect the input voltage IPV of the power supply module 20, and then output the value of the input voltage IPV to the digital microprocessor 12. The digital microprocessor 12 receives the value of the input current IPI and the value of the input voltage IPV to calculate the value of the input power IPW.
Reference is made to FIG. 2 which is a schematic circuit block diagram of a prior art apparatus and a method for measuring the amount of current in battery cells using a plurality of sensing resistors. The apparatus and method for measuring the amount of current in battery cells using a plurality of sensing resistors are disclosed in TW Patent I301899. The apparatus includes a plurality of resistors R1, R2, R3, a main chip 201, a multiplexer 202, and a plurality of switches S1, S2, S3. The resistors R1, R2, R3 are connected in parallel to measure the amount of current in battery cells C1, C2, C3, C4. The main chip 201 is connected to each of the resistors R1, R2, R3 to detect the amount of the voltage across the resistors R1, R2, R3 so that the amount of current can be summed up according to the detected voltage values. When the summed amount of current exceeds a predetermined threshold value, another resistor is selected by the multiplexer 202. The switches S1, S2, S3 are connected to the resistors R1, R2, R3, respectively, and are controlled to be turned on or turned off by an output signal produced by the multiplexer 202. Accordingly, heat generated from the individual resistor can be dissipated to prevent damaging surrounding components and the amount of current can be accurately detected.
The battery cells C1, C2, C3, C4 are connected in parallel to the resistors R1, R2, R3 so that the current in battery cells C1, C2, C3, C4 flows through the resistors R1, R2, R3. Because the battery cells C1, C2, C3, C4 are connected in parallel to the resistors R1, R2, R3 with different resistance values, currents outputted from the battery cells C1, C2, C3, C4 will be distributed and flows through the resistors R1, R2, R3. First, the current from the battery cells C1, C2, C3, C4 flows through the resistor R1, the main chip 201 detects the voltage across the resistor R1, and then adds up it as an amount of current. The amount of current added up reaches a predetermined threshold value with the lapse of time. When the amount of current detected at the resistor R1 reaches the predetermined threshold value, the main chip 201 instructs the multiplexer 202 to switch on the switch S2 of the resistor R2. On the basis of the instruction of the main chip 201, the multiplexer 202 switches on the switch S2. Accordingly, the current from the battery cells C1, C2, C3, C4 is distributed and flows through the resistors R1 and R2. The main chip 201 detects the voltage across each of the resistors R1 and R2, and adds up each amount of current. Similarly, the amount of current added up reaches a predetermined threshold value with the lapse of time.
When the amount of current detected at the resistors R1 and R2 reaches the predetermined threshold value, the main chip 201 instructs the multiplexer 202 to switch on the switch S3 of the resistor R3. On the basis of the instruction of the main chip 201, the multiplexer 202 switches on the switch S3. Accordingly, heat generated from the individual resistor can be dissipated to prevent damaging surrounding components and the amount of current can be accurately detected.
Accordingly, the power detection apparatus disclosed in TW Patent M385003 can be provided to accurately detect consumed power of the load and the power supply in a single power-supplying, and further in multiple power-supplying loops. In addition, the apparatus for measuring the amount of current in battery cells using a plurality of sensing resistors disclosed in TW Patent I301899 can be provided to prevent damaging surrounding components because heat generated from the individual resistor can be dissipated by using the multiplexer to switch on the switches and the amount of current can be accurately detected. However, the two patents do not disclose that a power measurement system for multiple power sources and a method of operating the same are provided to calculate output powers of different power sources by using a multiplexer which is connected to the power sources and controlling the multiplexer via external selection signals.